#chemical_group__group__radical  (chemistry) two or more atoms bound together as a single unit and forming part of a molecule
  supertype:  building_block__unit  a single undivided natural entity occurring in the composition of something else; "units of nucleic acids"
  subtype:  acyl_group  alcohol_group  aldehyde_group  alkyl_radical  allyl_radical  azido_group  azo_group  benzyl_radical  benzoyl_group  cacodyl_radical  carbonyl_group  carboxyl_group  chromophore  cyano_group  glyceryl  hydrazo_group  hydroxyl_radical  ketone_group  methylene_group  propyl_radical  nitrate  nitrite  uranyl_radical  vinyl_radical
  part of:  molecule  (physics and chemistry) the simplest structural unit of an element or compound

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